Does winter's bite feel exceptionally sharp this year? Has the Polar Vortex sucked all memories of summer from your mind? Lost track of winter storm names? It may come as a surprise then to learn that 2013 was one of the warmest years globally since 1880 (either seventh or ninth, depending on the data set used*). In fact, the ten warmest years on record have all occurred since the millennium (with the exception of 1998) with 2005 and 2010 tied for the warmest.

This news comes from NASA's Goddard Institute for Space Studies (GISS) in New York City, who released the findings today.

It might be hard to believe for many Americans who've spent the last few weeks on snow shovel duty, but global warming is very much alive and well (despite what some rabid deniers may have recently claimed.) And even though 2013 may only have been the 42nd warmest year on record for the U.S., other places - like Australia - experienced their hottest year ever.

"Long-term trends in surface temperatures are unusual and 2013 adds to the evidence for ongoing climate change," GISS climatologist Gavin Schmidt said. "While one year or one season can be affected by random weather events, this analysis shows the necessity for continued, long-term monitoring."

A major contributor to Earth's rapidly rising temperature is carbon dioxide, a greenhouse gas that traps heat energy from solar radiation. While carbon dioxide emissions do of course occur naturally, the past hundred-plus years of industrious human activity worldwide have greatly helped boost global CO2 levels to over 400 parts per million - higher than it has been for the past 800,000 years.

Even solar activity, which waxes and wanes on fairly regular 11-year cycles, has been found to play a rather minimal role in recent global warming.

And as far as the oft-quoted "no warming since 1998″ claim goes - ongoing studies have found that missing data from remote locations in the Arctic and Africa may actually contain the "missing heat," not to mention that warming has indeed continued deep below the ocean's surface.

Speaking of the ocean, observed decadal variability in global temperatures is greatly affected by El Niño/La Niña events: massive periodic warm- and cold-water current shifts in the equatorial Pacific. With an El Niño expected this summer, 2014 could be another global hot one - perhaps topping the charts yet again.

"Assuming that an El Niño begins in summer 2014, 2014 is likely to be warmer than 2013 and perhaps the warmest year in the instrumental record. However, given the lag between El Niño initiation and global temperature, 2015 is likely to have a temperature even higher than in 2014."

If this all helps make you feel a little bit warmer, well... sorry about that.

Video: The visualization at the top shows how global temperatures have risen from 1950 through the end of 2013. Credit: NASA/GSFC.

*Published results from GISS differ by a few hundredths of a degree uncertainty from complementary research by Columbia University climatologist Dr. James Hansen, altering the rankings of warmest years. (PDF here.)